4-154 As shown in figure 4-154, there is a steel plate whose original length is L=1m: the elastic modulus of the steel plate: Physics Assignment, NUS, Singapore

4-154 As shown in figure 4-154, there is a steel plate whose original length is L=1m: the elastic modulus of the steel plate is E=2.1×10kg •f/cm². =120Ω: sensitivity coefficient K=2), the measured tensile strain is 300με.

Find: elongation of the steel plate ΔL: ΔR/R of the σ strain gauge: if Iμε is to be measured, what is the corresponding ΔR/R?

4-155 There is a resistance strain gauge, its sensitivity S=2, R=1202. Assume that the strain gauge is 1000 when working and ask its AR=?

If this strain gauge is connected to the circuit shown in Figure 4-155, try to find:

(1) Indicated value of current without strain:
(2) Current indication value when there is strain:
(3) The relative change of the Indic anal value Of the ammeter
(4) Whether this change can be read from the table.